Abstract: A method includes providing a tapered roller bearing including an outer ring having a raceway surface, an inner ring having a raceway surface and a plurality of tapered rollers each having a rolling surface and a large end-face; optimizing a surface roughness of at least one surface selected from the following set of surfaces: the outer ring raceway surface, the inner ring raceway surface, the rolling surfaces of the tapered rollers and the large end faces of the tapered rollers; and black oxidizing the at least one first surface.

Abstract: A bearing cage for holding rollers between an outer ring and an inner ring of a bearing includes a first side ring, a second side ring axially spaced from the first side ring and a plurality of circumferentially spaced bridges connecting the first side ring and the second side ring. The first side ring includes at least one radially inward extending circumferential projection, and the at least one projection may be a plurality of projections separated by a plurality of gaps.

Abstract: The invention provides a seal for a taper roller bearing. The seal includes: a frame having: an outer flange, extending radially outward, an inner flange, extending radially inward, an middle flange, located between the outer flange and the inner flange and extending in an axial direction. The outer flange, the inner flange and the middle flange are integrally formed; a sealing ring, at least connects and covers the radial outer side of the outer flange of the frame, and has at least one sealing lip extending outward in the radial direction. The invention also provides an assembly for a taper roller bear, which provides a taper roller bearing. An inn ring of that taper roller bearing has a shoulder with a large flange; and a seal as described above. The middle flange is in interference fit with the outer circumferential surface of the shoulder, and the inner flange presses against and covers at least a part of the large flange.

Abstract: Provided is a gravity gradient measurement apparatus and measuring method, wherein a turntable rotates horizontally around an earth-vertical axis, a vacuum layer is arranged on the turntable defining a first chamber, a first three-axis accelerometer and a second three-axis accelerometer are located in the first chamber, the first three-axis accelerometer and the second three-axis accelerometer are arranged symmetrically on an x axis with respect to an origin of coordinates. Both the first three-axis accelerometer and the second three-axis accelerometer have a distance of R from the origin of coordinates. The first three-axis accelerometer and the second three-axis accelerometer are arranged symmetrically on an z axis with respect to the origin of coordinates, and the first three-axis accelerometer and the second three-axis accelerometer are spaced at a distance of h on the z axis. The measurement module uses measurements of the accelerometers to determine gravity gradients on the coordinate axes.

Abstract: Provided is a gravity gradient measurement apparatus and measuring method, wherein a turntable rotates horizontally around an earth-vertical axis, a vacuum layer is arranged on the turntable defining a first chamber, a first three-axis accelerometer and a second three-axis accelerometer are located in the first chamber, the first three-axis accelerometer and the second three-axis accelerometer are arranged symmetrically on an x axis with respect to an origin of coordinates. Both the first three-axis accelerometer and the second three-axis accelerometer have a distance of R from the origin of coordinates. The first three-axis accelerometer and the second three-axis accelerometer are arranged symmetrically on an z axis with respect to the origin of coordinates, and the first three-axis accelerometer and the second three-axis accelerometer are spaced at a distance of h on the z axis. The measurement module uses measurements of the accelerometers to determine gravity gradients on the coordinate axes.